1. Field of the Invention
The present invention relates to an etching apparatus, more particularly to an etching apparatus which etches a wafer, of which reverse has been ground by a planarization apparatus, and then automatically mounts the wafer on a wafer frame for dicing.
2. Description of Related Art
Demands have been increasing to make thinner semiconductor elements because of the needs of the elements for IC cards. Then, after predetermined circuit patterns are formed on the obverse of a semiconductor wafer, the reverse of the wafer is ground by a planarization apparatus such as a back grinder so as to make a thin semiconductor wafer.
However, a fracture layer is formed on the reverse of the semiconductor wafer by the back grinding, and the fracture layer results in lower strength of the semiconductor wafer. In view of the disadvantage, the ground reverse of the semiconductor wafer is processed with an etching process in order to remove the fracture layer.
The semiconductor wafer that is etched after the back grinding as described above is mounted on a wafer frame after separating a protecting sheet, which is adhered for protecting the obverse of the wafer at back grinding. Then, the semiconductor wafer is supplied to a dicing machine while being mounted on the wafer frame, and the semiconductor wafer is diced into individual elements by the dicing machine.
In such a conventional method, the separation of the protecting sheet and the mounting of the wafer on the wafer frame are performed by an operator all manually. However, the semiconductor wafer that is made thin by etching is difficult to handle, and yield is lower.
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of an etching apparatus that can automatically mount the etched wafer on the wafer frame.
In order to achieve the above-described objects, the present invention is directed to an etching apparatus, comprising: an etching part which holds an obverse of a wafer with a chuck by suction, the chuck being movable up and down and rotatable, then supplies etching liquid to a reverse of the wafer while rotating the wafer in a processing vessel so as to etch the reverse of the wafer, then jets a cleaning liquid to the reverse of the wafer while rotating the wafer so as to clean the reverse of the wafer, and then jets air to the reverse of the wafer while rotating the wafer so as to dry the reverse of the wafer; a wafer supply part which supplies the wafer to the etching part; a mount part which receives a wafer frame at a wafer frame receiving position, then moves relatively to an upper part of the processing vessel, then mounts the wafer on the wafer frame by adhering the reverse of the wafer that is transported to the upper part by the chuck to an adhesive sheet together with the wafer frame so as to mount the wafer on the wafer frame, and then returns to the wafer frame receiving position; a wafer frame supply part which supplies the wafer frame to the mount part which is positioned at the wafer frame receiving position; and a wafer frame collection part which collects the wafer frame from the mount part having returned at the wafer frame receiving position.
According to the present invention, the wafer is first supplied to the etching part by the wafer supply part. The obverse of the wafer, supplied to the etching part, is held by suction with the chuck which can move up and down and can rotate. Then, the wafer is rotated in the processing vessel while the etching liquid is supplied to the reverse of the wafer so as to etch the wafer. After the etching is completed, the wafer is again rotated in the processing vessel while the cleaning liquid is jetted to the reverse of the wafer so as to clean the wafer. Then, the cleaned wafer is still again rotated in the processing vessel while the air is supplied to the reverse of the wafer so as to dry the wafer. After the cleaning and the drying of the wafer are completed, the mount part which has received the wafer frame from the wafer frame supply part at the wafer frame receiving position moves to the upper part of the processing vessel. Then, the chuck moves up to the mount part which has moved to the upper part of the processing vessel, and the reverse of the wafer is adhered to the adhesive sheet together with the wafer frame, thereby the wafer is mounted on the wafer frame. The mount part that includes the wafer frame and the wafer mounted on the wafer frame returns to the wafer frame receiving position, and the wafer frame collecting part collects the wafer frame from the mount part that has returned to the wafer frame receiving position. By the process described above, the etched wafer can be mounted on the wafer frame in an automatic manner.